Osteoma of skull is a common benign tumor, which is mainly manifested as a circular or conical protuberance protruding from the outer plate of skull top, with different sizes and diameters ranging from several millimeters to several centimeters. It has no adhesion, tenderness and discomfort with scalp, and generally does not cause special symptoms except appearance deformation. Clinically, skull osteoma should be differentiated from diseases such as frontal medial plate hyperplasia, skull fibrous dysplasia, meningioma and bone fibrous dysplasia. 1. Frontal plate hyperplasia: Frontal plate hyperplasia presents wave-like bone hyperplasia, and patients often have symptoms such as headache, obesity and decreased libido. More common in postmenopausal women, sometimes accompanied by diabetes or diabetes insipidus. 2. Fibrodysplasia of skull: Fibrodysplasia of skull has a wide range of lesions, a wide base and multiple lesions, involving the lamina and skull plate. Other bones in the whole body can also occur, with a unilateral trend. 3. Meningioma: Meningioma grows rapidly, showing non-plastic new bone hyperplasia and osteoid changes. The tumor base is wide, and the skull plate may have osteolytic changes. The increase of blood supply of tumor leads to the widening and enlargement of the shadow of vascular sulcus nearby. 4. Fibrodysplasia of bone: Fibrodysplasia of bone has a wide range of lesions, mostly at the top of the orbit and changes in the face. On X-ray plain film and CT, the whole skull is involved, the boundary is unclear, the density is inconsistent, and there may be flat bone changes in other parts of the body.